public void Post_FitToWork_ReturnsOk() {
// Arrange
var questionnaire = new UserQuestionnaireModel { };
var questionnaireResult = new QuestionnaireResult { IsFitToWork = true, UserMessage = "FitToWork" };
_mockUserService.Setup(m => m.SubmitUserQuestionnaire(questionnaire))
.Returns(questionnaireResult);
// Act
var response = _controller.Post(questionnaire);
// Assert
Assert.AreEqual(HttpStatusCode.OK, response.StatusCode, "Expected OK");
var result = JsonConvert.DeserializeObject<QuestionnaireResult>(response.Content.ReadAsStringAsync().Result);
Assert.AreEqual(questionnaireResult.IsFitToWork, result.IsFitToWork);
Assert.AreEqual(questionnaireResult.UserMessage, result.UserMessage);
_mockUserService.Verify(m => m.SubmitUserQuestionnaire(questionnaire), Times.Once, "Expected questionnaire to be submitted");
}